One of the most interesting, refined startups I've seen in the "rewarded, opt-in" ad marketplace is Dabbl, an app that pays users a 5 cents credit per completed engagement. When users accrue $5 worth of value, they can redeem it for a gift card. Dabbl is all about testing, learning and delivering the best ROI possible for both sides of the marketplace: consumer and brands.

New scientific research indicates video may be less effective than standard or animated banner ads in terms of actually seeing or experiencing an ad's exposure. The research, conducted by Media Science for a study commissioned by Kargo, utilized neuroscientific methods to measure the biometric responses of 218 smartphone users to three ad formats: standard banners (300x50 and 300x250), animated units, and video units (various sizes). It should be noted that Kargo markets custom-animated units to the ad industry.